Naming of HEq_sc

[Matthew Pickering]

Hi all,

Does anyone know why the *record selector* `HEq_sc` started with a
capital letter?

Would it be sensible to rename it to start with a lower case letter
and perhaps mention that it is a selector in the name?

git grep "HEq_sc" doesn't yield any explanation, I could only work
this out from reading the source doe.

I propose "heq_sel" could be more self-explanatory.

Cheers,

Matt